Im sure my long suffering neighbours were delighted to hear the song of the FWE as it broke into sustained running, its a bit loud! but not too bad anyway i filmed the test and attached it here for your viewing pleasure.

The Dimesions are listed on the film, it is quite sensitive to small changes so i recorded it on the film, thats what you can hear me muttering at the begining of the film "110mm", any guesses on what im saying at the end.?

Now that i have it running i can start the other tests regarding carburation.

Hopefully we now also have some exact results for Graham to plug into UFlow as well.

Enjoy!

Nick

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Nick, that was an interesting start. Kind of makes one appreciate how you can be so close to something working, if you didn't press on, one might miss something right under their nose, or just over the horizon.
And too, I've felt the same with the pop, pop, bang, bang effect, how it starts to weigh on you because of the concern for neighbors. I remember one woman two houses down thinking I was shooting off rockets, when if fact it was just my snorekeler not catching. Instead of chuffing after an intial exhalation, it woud shoot out a quick blast of air, not an explosion, just an energetic screechy hiss.
Mark

You needn't have the recuperator, just put a dam (plate) in front of the intake, attached to the moving thrust carriage, far enough that it doesn't screw with the engine. I did a small(ish) block about 5" in front.

You get then the contribution of the tail only, with no accidental augmentation.

Then remove the plate, and get the tail minus intake number. That's all the info you need.

Nice one Mike!,
Larry, i saw a nice bit of PVC tubing that would probably do the job for shortish runs, it doesnt get that hot out front, Even Cheaper :-)

I was thinking about measuring thrust and thought the most accuarate way would be to rig up a simple pulley system counter balanced with small weighs/lumps of metal of a know weight, or just pile stuff on untill the carriage moves back, then just wieght the lot on kitchen scales.?.

Nick wrote:I was thinking about measuring thrust and thought the most accuarate way would be to rig up a simple pulley system counter balanced with small weighs/lumps of metal of a know weight, or just pile stuff on untill the carriage moves back, then just wieght the lot on kitchen scales.?.

Nick

Nick -

Another good way I though of for accurate measurement of small thrust values would be a heavy, sealed hollow cylinder [weighted at the bottom end] that would just sink in water. As the engine moves forward, it would pull the cylinder up out of the water until the un-buoyed weight would be equal to thrust. But, of course, it would need to be calibrated with some trusted scale to start with, so there's probably no real advantage to it.

I still fail to understand what's wrong with the methods used by Werner von Braun, Paul Schmidt et al.

(1) they used ordinary scales;

(2) they tested their machines in vertical position, exhaust upwards.

If you use normal scales, they are already calibrated, made linear etc. etc. You just read off the thrust value, like the weight of a sack of potatoes.

Schmidt (and Reynst) also used the vertical position to great advantage by using a flue above the engine to carry a lot of the noise and all the exhaust gas away into a fairly ordinary chimney. The research staff apparently appreciated that a lot.

Random thoughts:
That works great for bigger engines, of course.
I suppose we could ignore any effects of mounting in a way we don't intend to use it...
If we really want to dyno tune these things, then you want a lot of resolution, and to vibration isolate between engine and scale.
Once I exceed the 10 lb of my force gage, I'll do exactly as you say, Bruno. Perhaps put a weight on the scale, then a blob of rubber, then the engine mount.
I have been using a kinked wire or a piece of rubber tube between force gage and engine to absorb the vibration. The vibration will make short work of any little mechanism inside the scale.

Mike Everman wrote:Random thoughts:
That works great for bigger engines, of course.
I suppose we could ignore any effects of mounting in a way we don't intend to use it...
If we really want to dyno tune these things, then you want a lot of resolution, and to vibration isolate between engine and scale.
Once I exceed the 10 lb of my force gage, I'll do exactly as you say, Bruno. Perhaps put a weight on the scale, then a blob of rubber, then the engine mount.
I have been using a kinked wire or a piece of rubber tube between force gage and engine to absorb the vibration. The vibration will make short work of any little mechanism inside the scale.

Mike -

That was one reason I still used my broken cinder block on the scale when I tried it with the old Elektra I. It would have worked, too, except that my leaf blower and shop vac blew a lot of gritty crud from my gravel driveway up into the body of the scale and locked it up pretty solid! It took a while to get it all shaken out again.